Feltria (Feltria) orientalis, Tuzovskij, Petr V. & Semenchenko, Ksenia A., 2009

Tuzovskij, Petr V. & Semenchenko, Ksenia A., 2009, New water mites species (Acariformes: Hydrachnidia) from the Far East of Russia, Zootaxa 2241, pp. 1-21 : 17-20

Feltria (Feltria) orientalis sp. n.

( Figs. 53–57 )

Type material. Holotype: female (245-kas– IBSS), Russia, Khabarovsk Territory, Chegdomynsky District, the Amur River basin, the Bureya River, N 51°06.036’; E 132°29.342’; depth 40 cm; substrates: stones, pebbles, medium-grained sand, 23.09.2005, leg. D.A. Sidorov. Paratypes: 1 female (246-kas– IBSS), Russia, Khabarovsk Territory, Chegdomynsky District, the Amur River basin, the Urgal River, N 51°09.942’; E 132°56.911’; depth 20 cm; substrates: stones, pebbles, medium-grained sand, detritus, 25.09.2005, leg. D.A. Sidorov; 1 female (247-kas– IBSS), Russia, Khabarovsk Territory, Chegdomynsky District, the Amur River basin, the the Bolshoy Chalbach River, N 50°33.588’; E 131°32.488’; depth 25 cm; substrates: boulders, stones, medium-grained sand, detritus, 20.09.2005, leg. D.A. Sidorov.

Description. Female. Dorsum with large central shield and four pairs of platelets ( Fig. 53 ) and similar to dorsum F. cornuta rossica Tuzoskij & Semenchenko (Tuzovskij & Semenchenko 2009) . Dorsal shield elongated (ratio length/width = 1.3), cross-shaped, with moderately developed lateral protrusion and bears two pairs of setae (Oi and Sci). Setae Fp, Hi, He, Sce, Li, Le, Ci and Pi located free on soft integument; setae Oe placed on first pair of lateral platelets, setae Si on fourth pair of lateral platelets, setae Fch, Vi and Ve on rather large sclerites. Setae Fp, Oi and Pi without glandularia, other idiosomal setae associated with glandularia. Setae Fch, Oe, Hi and Sci thick, other idiosomal setae thin. First and second pairs of lateral platelets nearly equal in size, fourth pair of lateral platelets much larger than third pair of lateral ones. First pair of lyriform organs (i1) placed on platelets, bearing setae and glandularia Vi, other four pairs of lyriform organs (i2 –i5) lying free on soft integument along lateral edges of body. Excretory pore plate large, slightly broader than long, located dorsally. Setae Pi and Ci separated.

All coxal groups separated ( Fig. 54 ). Posterior apodemes of first coxae short and directed laterally. Second coxae not extending to midline. Posterior extensions of fourth coxae slightly developed. Acetabular plates separated, with numerous genital acetabula, three thin median setae and one central seta on each side; acetabula situated in two groups: anteromedial (5–7) and numerous (25–41) in central and lateral portions. Acetabular plates with rounded anteromedial and posteromedial corners. Pregenital sclerite relatively small, located between posteromedial corners of posterior extensions of fourth coxae and platelets bearing setae Pe. Anterior genital sclerite triangular. Setae Pe and Se with associated glandularia lying free on soft integument between posterior extensions of fourth coxae and genital area. Sclerites bearing setae Pe slightly larger than Se. Ventrolateral platelets narrow, transverse and lying free between fourth coxae and lateral portions of acetabular plates.

Trochanter of pedipalp ( Fig. 55 ) relatively short, with single dorsodistal seta. Femur well expanded, with three proximal and two stout dorsodistal setae, its ventral margin convex; genu with two short proximal spines and two relatively long dorsodistal setae; tibia long with unequal ventrodistal setae and one dorsodistal thin seta.

First four segments of all legs with stout setae, tibia and tarsus of leg I with thin setae, tibia II–IV with stout setae ( Fig. 56 ). Trochanter of legs IV with three thick dorsal setae. Claws with three clawlets: short external, large median and internal, external and median clawlets with acute tips, internal clawlet with rounded tip ( Fig. 57 ).

Measurements (n=3). Length of body 343–396, width 270–363; length of dorsal shield 211–242, width 185–191; length of seta Fch 23–27; length of posteromedian dorsal plate 42–44, width 60–70; length of coxae I–II 130–132, width 60–78; length of coxae III–IV 138–155, width 112–134; length of genital plates 85–95, width 92–130; length of anal plate 30–51, width 34–64; length of basal segment of chelicera 68–80, length of cheliceral stylet 18–22; length of pedipalpal segments (P-1–5): 15–20, 50–54, 30–34, 64–72, 34–37; length of leg segments: I-L- 1–6 – 27–30, 34–40, 35–40, 44–55, 54–78, 64–85; II-L- 1–6 – 30–35, 34–42, 35–39, 49–52, 54–64, 70–72; III-L- 1–6 – 34 –40, 37–39, 38–45, 58–64, 68–79, 84–88; IV-L- 1–6 – 51 –70, 34–48, 44–54, 68– 82, 78–85, 88–102.

Male. Unknown.

Differential diagnosis. The present species is similar to the European representatives of the armata - group, in which Bader included the following species: Feltria armata Koenike, 1902 ; F. brevipes Walter, 1907 ; F. s h u s t e r i Bader, 1974 ( Bader 1973, 1974). Lundblad (1956) considered F. b re v i p e s a juniour synonym of F. a r m a t a. Among the armata -group, F. orientalis sp. n. is more similar to F. b re v i p e s. The dorsal shield in females of F. brevipes have more or less developed lateral protrusions, in females of F. armata and F. shusteri the dorsal shield is without lateral protrusions ( Bader 1973, 1974). According to redescription of F. a r m a t a females of this species also has developed lateral protrusions of dorsal shield (Gerecke et al. 2009). Feltria orientalis sp. n. differs from F. brevipes in the following characters (character states of F. brevipes are indicated in parentheses from Bader 1973): the pedipalpal genu with four setae (two setae), length of the pedipalpal tarsus 34–37 μm (43–46 μm), the ratio length of the dorsal shield/length of the idiosoma = 0.61– 0.66 (0.44–0.54), the third pair of the dorsolateral plates and sclerites, bearing setae Li, are separated (usually fused to each other), acetabula arranged mainly in central and lateral portions of the genital plates (mainly in the peripheral position).

Etymology. The species epithet orientalis is derived from the eastern position of the region where it was collected.

Habitat. Running waters.

Distribution. Khabarovsk Territory, Far East of Russia.

Figures

FIGURES 53 – 54. Feltria orientalis sp. n., female: 53, idiosoma, dorsal view; 54, idiosoma, ventral view. Scale bar = 100 µm.

FIGURES 55 – 57. Feltria orientalis sp. n., female: 55, pedipalp; 56, leg IV; 57, claw of leg IV. Scale bars = 50 µm for Fig. 56; 25 µm for Figs. 55, 57.